jap banner
  • Volume/Page
  • Keyword
  • DOI
  • Citation
  • Advanced
   
 
 
 

Flickr Twitter UniPHY Group iResearch App Facebook

BROWSE VOLUMES

Year Range: 
Search Issue | RSS Feeds RSS
Previous Issue Next Issue

1 Feb 2006

Volume 99, Issue 3, Articles (03xxxx)

Page 1 of 4 Pages Next Page | Jump to Page
back to top
RSS Feeds

Adhesive wafer bonding

F. Niklaus, G. Stemme, J. -Q. Lu, and R. J. Gutmann

J. Appl. Phys. 99, 031101 (2006); http://dx.doi.org/10.1063/1.2168512 (28 pages) | Cited 65 times

Online Publication Date: 9 February 2006

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Wafer bonding with intermediate polymer adhesives is an important fabrication technique for advanced microelectronic and microelectromechanical systems, such as three-dimensional integrated circuits, advanced packaging, and microfluidics. In adhesive wafer bonding, the polymer adhesive bears the forces involved to hold the surfaces together. The main advantages of adhesive wafer bonding include the insensitivity to surface topography, the low bonding temperatures, the compatibility with standard integrated circuit wafer processing, and the ability to join different types of wafers. Compared to alternative wafer bonding techniques, adhesive wafer bonding is simple, robust, and low cost. This article reviews the state-of-the-art polymer adhesive wafer bonding technologies, materials, and applications.
Show PACS
85.40.-e Microelectronics: LSI, VLSI, ULSI; integrated circuit fabrication technology
61.41.+e Polymers, elastomers, and plastics
01.30.Rr Surveys and tutorial papers; resource letters
back to top
RSS Feeds

Simulation of the writing on the patterned optical phase-change recording media

Evan Small, Yizhang Yang, Sadegh M. Sadeghipour, and Mehdi Asheghi

J. Appl. Phys. 99, 033101 (2006); http://dx.doi.org/10.1063/1.2165411 (8 pages) | Cited 1 time

Online Publication Date: 1 February 2006

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Irregularities in the edge of the bit marks is one of the most critical sources of the noise that lead to timing jitter in optical phase change recording. The maximum linear bit density achievable at a given wavelength and lens numerical aperture is often limited by jitter. Jitter is largely determined by the combined optical, thermal, and crystallization properties of the medium and by the optical quality and recording strategy of the laser beam. Media with a patterned phase-change layer are proposed for controlling the mark edge jitter by making distinct mark edges. The preliminary simulation results from writing on the transverse and longitudinal patterns look promising in producing rectangular bit marks with distinct boundaries. The bit marks written on patterned media also have a smaller size compared to those written on continuous media. An interesting and unexpected result is the disappearance of the crescent-shaped trailing edge in all the bit marks on the patterned media, the shape and existence of which can have a great effect on the trailing edge jitter. Writing on grooved media has also been simulated for further comparison. In the present investigation a simulation code is developed using commercial finite element analysis software for the heat transfer simulation, with a custom-integrated crystallization model.
Show PACS
42.79.Vb Optical storage systems, optical disks
47.11.Fg Finite element methods
64.70.D- Solid-liquid transitions

Spectral analysis of a three-dimensional photonic quantum ring laser with a square microcavity

Sung-Jae An, Junho Yoon, Jawoong Lee, O'Dae Kwon, and Vladimir G. Minogin

J. Appl. Phys. 99, 033102 (2006); http://dx.doi.org/10.1063/1.2168236 (5 pages) | Cited 2 times

Online Publication Date: 6 February 2006

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Three-dimensional photonic quantum ring lasers with a square microcavity were fabricated and their spectra were explained by combining two conditions: the off-normal Fabry-Pérot resonance and quadruple-bounced whispering-gallery mode. The angular distribution of the emission modes and their discrete wavelengths were in excellent agreement with a three-dimensional Rayleigh-Fabry-Pérot model. The three-dimensional model also showed that the slope of the spectral mode spacing and the value of the angular mode spacing as a function of the length of a square side L are inversely proportional to L2 and L, respectively.
Show PACS
42.55.Px Semiconductor lasers; laser diodes
42.60.By Design of specific laser systems
42.55.Sa Microcavity and microdisk lasers
42.60.Da Resonators, cavities, amplifiers, arrays, and rings

Design of a GaN/AlGaN intersubband Raman laser electrically tunable over the 3–5 μm atmospheric transmission window

Greg Sun, Jacob B. Khurgin, and Richard A. Soref

J. Appl. Phys. 99, 033103 (2006); http://dx.doi.org/10.1063/1.2169349 (6 pages) | Cited 1 time

Online Publication Date: 10 February 2006

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Design results aimed at achieving tunable high-temperature operation in the 3–5 μm atmospheric transmission window are presented for the intersubband Raman lasers based on GaN/AlGaN coupled quantum wells. The ultrafast longitudinal-optical-phonon (LO-phonon) scattering in GaN/AlGaN quantum wells (QWs) can be used for the rapid depopulation of the lower laser state, while the large LO-phonon energies ( ∼ 90 meV) allow for a design to minimize the thermal population of the lower laser state, and are therefore beneficial for obtaining high-temperature operation. The Raman gain is proportional to the difference between the virtual lifetime of the upper laser state and the effective lifetime of the lower laser state instead of the real lifetimes. The advantage is that these lifetimes can be tuned with the detuning of the pump photon energy from the subband energy separation. At a fixed pumping wavelength of 2.7 μm, the tuning range of 3.6–5.2 μm is predicted with a moderate Raman gain of at least 100/cm as the electric field is varied. Furthermore, the output power of this laser is unlikely to saturate because of the intrinsically short intersubband lifetimes in the GaN-based QWs.
Show PACS
42.60.By Design of specific laser systems
42.55.Px Semiconductor lasers; laser diodes
42.55.Ye Raman lasers
42.60.Fc Modulation, tuning, and mode locking

Measuring the electron temperature by optical emission spectroscopy in two temperature plasmas at atmospheric pressure: A critical approach

A. Yanguas-Gil, J. Cotrino, and A. R. González-Elipe

J. Appl. Phys. 99, 033104 (2006); http://dx.doi.org/10.1063/1.2170416 (6 pages) | Cited 20 times

Online Publication Date: 13 February 2006

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The measurement of the electron mean kinetic energy by identifying the electron temperature and the excitation temperature obtained by optical emission spectroscopy is theoretically studied for two temperature argon plasmas at atmospheric pressure. Using a 32-level collisional radiative model in which both electron impact and argon-impact inelastic collisions are taken into account, it has been found that under certain conditions the argon inelastic collisions may cause a decrease of the argon excitation temperature so that the relation Te>Texc>T0 is satisfied. This inequality also appears when electron losses due to diffusion are important and the electron density is lower than its equilibrium value.
Show PACS
52.70.Kz Optical (ultraviolet, visible, infrared) measurements
52.25.Os Emission, absorption, and scattering of electromagnetic radiation
52.20.Fs Electron collisions
52.20.Hv Atomic, molecular, ion, and heavy-particle collisions
52.25.Fi Transport properties
back to top
RSS Feeds

Particle growth in silane-hydrogen discharges

Damir Kujundzic and Alan Gallagher

J. Appl. Phys. 99, 033301 (2006); http://dx.doi.org/10.1063/1.2168230 (5 pages) | Cited 3 times

Online Publication Date: 3 February 2006

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The growth of silicon particles has been measured in silane-hydrogen radio-frequency (rf) discharges using a typical hydrogen/silane dilution ratio (20) and the pressure range (1.2–2.2 Torr) used for the production of amorphous and microcrystalline silicon films and devices. By operating brief discharges without gas flow, the particle size is obtained from the afterglow diffusion and the particle density from the scattered-light intensity. These small-reactor data thus provide the expected particle size and density versus location-in a commercial large-area–isothermal-flowing-gas reactor. Particle growth rate is a strong function of pressure, whereas film growth rate is almost independent of pressure. Both growth rates are sensitive to rf voltage, although particle growth is more sensitive.
Show PACS
81.05.Cy Elemental semiconductors
81.05.Gc Amorphous semiconductors
52.77.Dq Plasma-based ion implantation and deposition
81.15.Gh Chemical vapor deposition (including plasma-enhanced CVD, MOCVD, ALD, etc.)
68.55.A- Nucleation and growth
52.80.Pi High-frequency and RF discharges

Radiative recombination of Ar2+ and enhanced dissociation of O2 in a glow discharge

Abdulaziz Al-Jalal and Mohammad Aslam Khan

J. Appl. Phys. 99, 033302 (2006); http://dx.doi.org/10.1063/1.2168241 (5 pages) | Cited 7 times

Online Publication Date: 9 February 2006

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We have recently reported a significant enhancement in the atomization of O2 in an Ar–O2 glow discharge. During our investigations of energy transfer between Ar and O2, we have observed a strong continuum emission from Ar2+ in the 350–600 nm spectral region in a pure Ar discharge. We believe that capture of a free electron by the Ar2+ ion leading to the formation of excited dimer Ar2* is responsible for this continuum. The dimer subsequently dissociates into Ar atoms. We further observe that in the presence of small amount of O2, resonant charge-exchanging collisions yield O2+ that subsequently capture free electrons and dissociate yielding up to a 30-fold increase in atomic O compared with the O-atom yield in pure O2 discharge. In addition, the Ar line at 763.5 nm appears to be fed by the dissociating Ar2*.
Show PACS
52.25.Os Emission, absorption, and scattering of electromagnetic radiation
52.80.Hc Glow; corona
52.20.Fs Electron collisions
52.20.Hv Atomic, molecular, ion, and heavy-particle collisions
52.70.Kz Optical (ultraviolet, visible, infrared) measurements

Electrical description of a magnetic pole enhanced inductively coupled plasma source: Refinement of the transformer model by reverse electromagnetic modeling

T. Meziani, P. Colpo, and F. Rossi

J. Appl. Phys. 99, 033303 (2006); http://dx.doi.org/10.1063/1.2164536 (7 pages)

Online Publication Date: 10 February 2006

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The magnetic pole enhanced inductively coupled source (MaPE-ICP) is an innovative low-pressure plasma source that allows for high plasma density and high plasma uniformity, as well as large-area plasma generation. This article presents an electrical characterization of this source, and the experimental measurements are compared to the results obtained after modeling the source by the equivalent circuit of the transformer. In particular, the method applied consists in performing a reverse electromagnetic modeling of the source by providing the measured plasma parameters such as plasma density and electron temperature as an input, and computing the total impedance seen at the primary of the transformer. The impedance results given by the model are compared to the experimental results. This approach allows for a more comprehensive refinement of the electrical model in order to obtain a better fitting of the results. The electrical characteristics of the system, and in particular the total impedance, were measured at the inductive coil antenna (primary of the transformer). The source was modeled electrically by a finite element method, treating the plasma as a conductive load and taking into account the complex plasma conductivity, the value of which was calculated from the electron density and electron temperature measurements carried out previously. The electrical characterization of the inductive excitation source itself versus frequency showed that the source cannot be treated as purely inductive and that the effect of parasitic capacitances must be taken into account in the model. Finally, considerations on the effect of the magnetic core addition on the capacitive component of the coupling are made.
Show PACS
52.50.Dg Plasma sources
52.70.Ds Electric and magnetic measurements
52.40.Fd Plasma interactions with antennas; plasma-filled waveguides
52.25.Fi Transport properties
02.70.Dh Finite-element and Galerkin methods

Characterization of radio frequency plasma using Langmuir probe and optical emission spectroscopy

M. Nisha, K. J. Saji, R. S. Ajimsha, N. V. Joshy, and M. K. Jayaraj

J. Appl. Phys. 99, 033304 (2006); http://dx.doi.org/10.1063/1.2171777 (4 pages) | Cited 5 times

Online Publication Date: 15 February 2006

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The radio frequency plasma generated during the sputtering of Indium Tin Oxide target using Argon was analyzed by Langmuir probe and optical-emission spectroscopy. The basic plasma parameters such as electron temperature and ion density were evaluated. These studies were carried out by varying the RF power from 20 to 50 W. A linear increase in ion density and an exponential decrease in electron temperature with rf power were observed. The measured plasma parameters were then correlated with the properties of ITO thin films deposited under similar plasma conditions.
Show PACS
52.70.Ds Electric and magnetic measurements
52.70.Kz Optical (ultraviolet, visible, infrared) measurements
52.25.-b Plasma properties
52.77.Dq Plasma-based ion implantation and deposition
81.15.Cd Deposition by sputtering
68.55.A- Nucleation and growth
back to top
RSS Feeds

Microstructural properties of solution-deposited La0.7Sr0.3MnO3 and LaMnO3 thin films

G. Kartopu and M. Es-Souni

J. Appl. Phys. 99, 033501 (2006); http://dx.doi.org/10.1063/1.2164534 (6 pages) | Cited 5 times

Online Publication Date: 1 February 2006

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The microstructural properties of solution-deposited La0.7Sr0.3MnO3 and nondoped LaMnO3 films have been studied. Several factors such as the choice of substrate, method of surface cleaning, annealing atmosphere, and precursor solution concentration were considered. Films with smoother surfaces were observed on SrTiO3 (100) and LaAlO3 (100) crystals, due to the near matching of the film-substrate lattice constants and thermal-expansion coefficients. In contrast, substrates such as Si (100) yield films with a rougher morphology. Variations in the crystalline quality and surface morphology of the films were demonstrated, simply by altering the precursor solution concentration and the surface condition of substrate. The local structure of the films was studied by Raman spectroscopy, which indicated enrichment in the oxygen content, differing from ideal oxygen stoichiometry (or from films annealed in inert gas atmosphere). This latter effect was shown to be more effective in the case of LaMnO3, where a structural transition from rhombohedral to orthorhombic was observed by changing the annealing atmosphere from ambient air to pure N2 gas, and is suggested to be the main origin of the anomalous conductivity increase reported in the literature in air or O2-annealed manganite films with respect to stoichiometric bulk La1−x(Sr,Ca)xMnO3.
Show PACS
68.55.-a Thin film structure and morphology
81.15.Lm Liquid phase epitaxy; deposition from liquid phases (melts, solutions, and surface layers on liquids)
68.55.A- Nucleation and growth
81.65.Cf Surface cleaning, etching, patterning
68.35.B- Structure of clean surfaces (and surface reconstruction)
78.30.Hv Other nonmetallic inorganics

Photocurrent pattern formation in polymer/methanofullerene blends imaged by near-field scanning photocurrent microscopy

C. R. McNeill and P. C. Dastoor

J. Appl. Phys. 99, 033502 (2006); http://dx.doi.org/10.1063/1.2165414 (7 pages) | Cited 7 times

Online Publication Date: 1 February 2006

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The dimensional dependence of micron-sized current inhomogeneities in poly[2-methoxy-5-(2′-ehtylhexyloxy)-1,4-phenylene vinylene]/1-(3-methoxycarbonyl)-propyl-1-1-phenyl-(6,6) C61 (MEH-PPV/PCBM) solar cells on processing conditions has been investigated. These current inhomogeneities typically consist of a central PCBM aggregate surrounded by a larger region of poor photocurrent production. For films spin coated from chlorobenzene, both the diameter of the current inhomogeneities and the size of the corresponding PCBM aggregates systematically increase with the time allowed for the film to dry. These observations indicate that the current inhomogeneities are a consequence of the nucleation and growth of the central PCBM cluster at the expense of PCBM from the surrounding area. In contrast to the results observed with chlorobenzene as the solvent, no micron-sized current inhomogeneities are observed using toluene as the solvent, despite the increased density of PCBM clusters in the film. The solubility of PCBM and the solvent volatility are identified as key parameters determining the formation of micron-sized current patterns. Also discussed is the influence of these current features on overall device performance, along with the influence of the film nanomorphology as processing conditions are changed.
Show PACS
72.40.+w Photoconduction and photovoltaic effects
84.60.Jt Photoelectric conversion
61.41.+e Polymers, elastomers, and plastics
68.55.-a Thin film structure and morphology
73.61.Ph Polymers; organic compounds
64.75.-g Phase equilibria

Temperature-dependent photoluminescence from patterned InAs quantum dots formed using metalorganic chemical vapor epitaxy

D. L. Huffaker, C. P. Hains, N. Nuntawong, Y. C. Xin, P. S. Wong, L. Xue, S. R. J. Brueck, and L. Lester

J. Appl. Phys. 99, 033503 (2006); http://dx.doi.org/10.1063/1.2165415 (4 pages) | Cited 9 times

Online Publication Date: 1 February 2006

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We analyze temperature-dependent photoluminescence (PL) behavior of patterned InAs/GaAs quantum dots (PQDs) formed by selective area epitaxy using metalorganic chemical vapor deposition. The processing scheme, described here, yields an ensemble of electronically isolated PQDs with PL characteristics that significantly differ from self-assembled (SA) QDs since neither a wetting layer nor neighboring QDs are available for coupling. The isolated nature of the PQDs supports a non-Fermi (nonequilibrium) carrier distribution which yields very different PL characteristics compared to the Fermi (equilibrium) distribution of the SAQDs especially at temperatures >100 K. Thus, the PQDs demonstrate a constant PL linewidth within the temperature range of 80–300 K along with improved temperature stability of PL intensity in comparison to SAQDs. The increased temperature stability allowed by electronic isolation may prove very important for high speed, temperature-insensitive QD laser development.
Show PACS
81.05.Ea III-V semiconductors
81.07.Ta Quantum dots
78.67.Hc Quantum dots
78.55.Cr III-V semiconductors
81.15.Gh Chemical vapor deposition (including plasma-enhanced CVD, MOCVD, ALD, etc.)
81.15.Kk Vapor phase epitaxy; growth from vapor phase

Self-assembling of Mg and O isoelectronic impurities in ZnS

V. A. Elyukhin and O. V. Elyukhina

J. Appl. Phys. 99, 033504 (2006); http://dx.doi.org/10.1063/1.2166644 (4 pages) | Cited 4 times

Online Publication Date: 1 February 2006

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Self-assembling of Mg and oxygen isoelectronic impurities in ZnS is presented. The occurrence of the 1O4Mg tetrahedral cells is predicted in ZnS-rich MgxZn1−xOyS1−y (x ≥ 4y) in the ultradilute oxygen impurity limit. Under certain conditions that are estimated for the lower growth and higher annealing temperatures of 300 and 500 °C, respectively, the alloys with the separated oxygen impurities surrounded by Mg atoms are more thermodynamically preferable than the random alloys. The origin of this phenomenon is a thermodynamic advantage of MgO and ZnS bonding over MgS and ZnO bonding and the smaller strain energy of the self-assembled alloys.
Show PACS
68.55.Ln Defects and impurities: doping, implantation, distribution, concentration, etc.
61.72.uj III-V and II-VI semiconductors
61.72.Cc Kinetics of defect formation and annealing
61.50.Lt Crystal binding; cohesive energy
68.60.Bs Mechanical and acoustical properties

Study on nitrogenated amorphous carbon films prepared by unbalanced magnetron sputtering

J. R. Shi

J. Appl. Phys. 99, 033505 (2006); http://dx.doi.org/10.1063/1.2168027 (7 pages) | Cited 5 times

Online Publication Date: 2 February 2006

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Nitrogenated amorphous carbon (a-CNx) films were prepared by unbalanced magnetron sputtering (UBMS) at different N2/Ar gas flow rate ratios and different bias voltages. The films were characterized using x-ray photoelectron spectroscopy, Raman scattering, nanoindenter, atomic force microscopy nanoscratch, and contact angle measurement. It was found that a negative bias of 150 V is the optimal condition for the formation of sp3 bonded carbon atoms. As the N2/Ar flow rate ratio changes from 0 to 0.47, the nitrogen to carbon ratio in deposited films increases from 0 to 0.22, and the sp3 fraction of carbon atoms decreases from 0.51 to 0.28. The pure carbon film has the highest sp3 faction of carbon atoms and therefore the highest hardness and the lowest scratching depth. Comparing to the films prepared by conventional magnetron sputtering, all the a-CNx films prepared by UBMS show a lower scratching depth. The a-CNx films have a hydrophilic characteristic with a surface free energy from 56.6 to 65.6 mN/m and a predominant polar component.
Show PACS
68.60.Bs Mechanical and acoustical properties
68.37.Ps Atomic force microscopy (AFM)
81.15.Cd Deposition by sputtering
79.60.Ht Disordered structures
78.35.+c Brillouin and Rayleigh scattering; other light scattering
81.40.Np Fatigue, corrosion fatigue, embrittlement, cracking, fracture, and failure

Electrical properties of multiple-layer structures formed by implantation of nitrogen or oxygen and annealed under high pressure

Irina V. Antonova, Andrzej Misiuk, and Charalampos A. Londos

J. Appl. Phys. 99, 033506 (2006); http://dx.doi.org/10.1063/1.2168233 (6 pages) | Cited 2 times

Online Publication Date: 2 February 2006

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Silicon-on-insulator-like structures formed in either oxygen- or nitrogen-implanted silicon during anneals under atmospheric and enhanced hydrostatic pressure are characterized by means of electrical techniques (current-voltage and capacitance-voltage measurements). It was found that the application of high pressure ( ∼ 1 GPa) stimulates the formation of a perfect top silicon layer and results in the degradation of the properties of the buried insulator. The latter effect is caused by defect accumulation in the buried insulator and leads to a decrease in the effective thickness of the insulator layer as extracted from capacitance-voltage measurements. Pressure-stimulated formation of electrically active centers (donors and acceptors) in the top silicon layer and substrate was found. The fixed charge in the oxide was found to be independent on the pressure applied during anneals, whereas the negative charge in the nitride increased with pressure.
Show PACS
73.40.Qv Metal-insulator-semiconductor structures (including semiconductor-to-insulator)
61.72.Cc Kinetics of defect formation and annealing
61.72.uf Ge and Si

Design of one-dimensional composite photonic crystals with an extended photonic band gap

V. A. Tolmachev, T. S. Perova, and K. Berwick

J. Appl. Phys. 99, 033507 (2006); http://dx.doi.org/10.1063/1.2165401 (5 pages) | Cited 6 times

Online Publication Date: 2 February 2006

Full Text: Read Online (HTML) | Download PDF

Show Abstract
A technique for photonic band gap (PBG) extension based on mixing photonic crystals with different lattice constants or filling factors is suggested. For the design of photonic crystals with maximal PBG extension the gap map imposition method is utilized. Gap maps for composite photonic crystals based on Si-air structures are calculated and used to predict optimal structures for fabrication.
Show PACS
42.70.Qs Photonic bandgap materials

Thermoelastic finite element modeling of laser generation ultrasound

Baiqiang Xu, Zhonghua Shen, Jijun Wang, Xiaowu Ni, Jianfei Guan, and Jian Lu

J. Appl. Phys. 99, 033508 (2006); http://dx.doi.org/10.1063/1.2168238 (7 pages) | Cited 5 times

Online Publication Date: 7 February 2006

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Thermoelastic finite element modeling of laser-generated ultrasound in aluminum plates is presented based on a numerical formulation for the transient response in terms of the characteristics of the source of the thermoelastic waves. The model accounts for the effects of thermal diffusion, as well as the finite width and duration of the laser source. The stress can be related to the laser energy and material properties. The numerical results indicate that the temperature dependence of the thermophysical parameters has a significant influence on the laser-generated surface-acoustic waves with high frequencies.
Show PACS
68.35.Iv Acoustical properties
62.65.+k Acoustical properties of solids
61.80.Ba Ultraviolet, visible, and infrared radiation effects (including laser radiation)
46.25.Hf Thermoelasticity and electromagnetic elasticity (electroelasticity, magnetoelasticity)

In situ stress evolution of Co films sputtered onto oxidized Si (100) substrates

M. Pletea, W. Brückner, H. Wendrock, R. Kaltofen, and R. Koch

J. Appl. Phys. 99, 033509 (2006); http://dx.doi.org/10.1063/1.2168243 (5 pages) | Cited 6 times

Online Publication Date: 7 February 2006

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The stress of magnetron-sputtered Co films of thicknesses up to 300 nm has been investigated in a wide range of sputter pressures (0.05-6 Pa) by a laser-based optical bending-beam setup. To correlate the thickness dependence of the stress with changes in the microstructure, the film morphology was investigated by focused ion beam, scanning electron microscopy, and atomic force microscopy. At all of the chosen sputter pressures the film stress is tensile. At low sputter pressures its evolution with film thickness can be related to the Volmer-Weber growth mode of medium-mobility metals and is similar to that of sputtered Cu films concerning nuclei density, island size, and island growth. At higher sputter pressures a transition to columnar grain growth takes place, accompanied by a decrease of the film density and an increase of the electrical resistance. The evolution of stress and microstructure with film thickness is discussed in the context of the stress models proposed in the literature.
Show PACS
68.60.-p Physical properties of thin films, nonelectronic
81.15.Cd Deposition by sputtering
68.55.A- Nucleation and growth
68.55.-a Thin film structure and morphology
68.35.B- Structure of clean surfaces (and surface reconstruction)
73.61.At Metal and metallic alloys

Effects of PbF2 doping on structure and spectroscopic properties of Ga2O3–GeO2–Bi2O3–PbO glasses doped with rare earths

Q. Y. Zhang, T. Li, D. M. Shi, G. F. Yang, Z. M. Yang, Z. H. Jiang, and S. Buddhudu

J. Appl. Phys. 99, 033510 (2006); http://dx.doi.org/10.1063/1.2169874 (4 pages) | Cited 9 times

Online Publication Date: 7 February 2006

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We report an intense room-temperature blue upconversion in Tm3+/Yb+3-codoped Ga2O3–GeO2–Bi2O3–PbO(PbF2) glasses upon excitation with a convenient 980 nm laser diode. Effects of PbF2 doping on the thermal stability, structure, and upconversion properties of Tm3+/Yb3+-codoped gallate-germanium-bismuth-lead glasses have been investigated. We find that the presence of PbF2 provides two potentials: shortening the ultraviolet cutoff band and decreasing the phonon energy of host glasses. The blue-upconversion intensity has a cubelike dependence on incident pump-laser power, indicating a three-photon process. Energy-transfer process and nonradiative phonon-assisted decay could be responsible for the population of the math emitting level of the Tm3+. The results indicate the potential possibility towards the development of an oxide-based blue-upconversion glass-fiber laser.
Show PACS
61.72.up Other materials
42.70.Ce Glasses, quartz
42.70.Hj Laser materials

The nonmonotonic dose dependence of optically stimulated luminescence in Al2O3:C: Analytical and numerical simulation results

R. Chen, V. Pagonis, and J. L. Lawless

J. Appl. Phys. 99, 033511 (2006); http://dx.doi.org/10.1063/1.2168266 (6 pages) | Cited 4 times

Online Publication Date: 7 February 2006

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Nonmonotonic dose dependence of optically stimulated luminescence (OSL) has been reported in a number of materials including Al2O3:C which is one of the main dosimetric materials. In a recent work, the nonmonotonic effect has been shown to result, under certain circumstances, from the competition either during excitation or during readout between trapping states or recombination centers. In the present work, we report on a study of the effect in a more concrete framework of two trapping states and two kinds of recombination centers involved in the luminescence processes in Al2O3:C. Using sets of trapping parameters, based on available experimental data, previously utilized to explain the nonmonotonic dose dependence of thermoluminescence including nonzero initial occupancies of recombination centers (F+ centers), the OSL along with the occupancies of the relevant traps and centers are simulated numerically. The connection between these different resulting quantities is discussed, giving a better insight as to the ranges of the increase and decrease of the integral OSL as a function of dose, as well as the constant equilibrium value occurring at high doses.
Show PACS
72.20.Jv Charge carriers: generation, recombination, lifetime, and trapping
78.55.Hx Other solid inorganic materials
61.72.J- Point defects and defect clusters

Silicide phase formation in Ni/Si system: Depth-resolved positron annihilation and Rutherford backscattering study

S. Abhaya, G. Amarendra, B. K. Panigrahi, and K. G. M. Nair

J. Appl. Phys. 99, 033512 (2006); http://dx.doi.org/10.1063/1.2168296 (4 pages) | Cited 4 times

Online Publication Date: 7 February 2006

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Silicidation in Ni/Si thin-film junction has been investigated using depth-resolved positron annihilation spectroscopy (PAS) and Rutherford backscattering spectrometry (RBS). Identification of various silicide phases from an analysis of the positron annihilation parameters is consistent with the RBS results. Absence of vacancy defects in the silicide region is clearly brought out by PAS.
Show PACS
68.35.Fx Diffusion; interface formation
78.70.Bj Positron annihilation
82.80.Yc Rutherford backscattering (RBS), and other methods of chemical analysis

Crystal structure and thermoelectric properties of the type-I clathrate compound Ba8Ge43 with an ordered arrangement of Ge vacancies

Norihiko L. Okamoto, Min Wook Oh, Takumi Nishii, Katsushi Tanaka, and Haruyuki Inui

J. Appl. Phys. 99, 033513 (2006); http://dx.doi.org/10.1063/1.2169869 (8 pages) | Cited 11 times

Online Publication Date: 8 February 2006

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The crystal structure of the type-I clathrate compound Ba8Ge43 has been investigated by x-ray diffraction and transmission electron microscopy. The thermoelectric properties of Ba8Ge43 have also been investigated. The crystal structure of Ba8Ge43 is different from that reported for the usual type-I clathrate compounds with the space group of Pmmathn but is a superlattice structure based on the usual type-I clathrate structure due to the ordering of Ge vacancies in half the 6c sites of the usual type-I clathrate structure. The crystal structure of Ba8Ge43 belongs to the space group of Iamathd and Ge vacancies exclusively occupy the 24c sites. The thermoelectric properties of Ba8Ge43 are not particularly good, as exemplified by the rather low ZT value of 0.057 because of the high value of electrical resistivity, which may arise from the existence of Ge vacancies.
Show PACS
61.66.Dk Alloys
72.15.Jf Thermoelectric and thermomagnetic effects
72.15.Eb Electrical and thermal conduction in crystalline metals and alloys
61.72.J- Point defects and defect clusters
68.37.Lp Transmission electron microscopy (TEM)

Ionization by impact electrons in solids: Electron mean free path fitted over a wide energy range

Beata Ziaja, Richard A. London, and Janos Hajdu

J. Appl. Phys. 99, 033514 (2006); http://dx.doi.org/10.1063/1.2161821 (9 pages) | Cited 17 times

Online Publication Date: 9 February 2006

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We propose a simple formula for fitting the electron ionization mean free paths in solids both at high and at low electron energies. The free-electron-gas approximation used for predicting electron mean free paths is no longer valid at low impact energies [(E−EF)<50 eV], as the band structure effects become significant at those energies. Therefore, we include the results of band structure calculations in our fit. Finally, we apply the fit to nine elements and two compounds.
Show PACS
71.20.-b Electron density of states and band structure of crystalline solids
72.10.Bg General formulation of transport theory

Optical properties of SrTiO3 thin films deposited by radio-frequency magnetron sputtering at various substrate temperatures

J. H. Ma, Z. M. Huang, X. J. Meng, S. J. Liu, X. D. Zhang, J. L. Sun, J. Q. Xue, J. H. Chu, and J. Li

J. Appl. Phys. 99, 033515 (2006); http://dx.doi.org/10.1063/1.2168029 (5 pages) | Cited 6 times

Online Publication Date: 9 February 2006

Full Text: Read Online (HTML) | Download PDF

Show Abstract
SrTiO3 thin films were deposited on vitreous silica substrates at various substrate temperatures (300–700 °C) by rf magnetron sputtering technique. The transition from amorphous phase to polycrystalline phase for the films occurred at the substrate temperatures of 300–400 °C. Their optical properties were investigated by transmittance measurements. The fitting method was used to calculate the refractive index and the film thickness from the transparent region of the transmittance spectra. The refractive index increased and the film thickness decreased with the substrate temperatures increasing. The dispersion of the refractive index was studied by considering a single electronic oscillator model. The band gaps of the films were estimated from Tauc’s law and showed a decreasing tendency to that of the bulk SrTiO3 with the substrate temperatures increasing. These results provide some useful references for the potential application of SrTiO3 films in integrated optics devices.
Show PACS
77.84.Ek Niobates and tantalates
77.84.Cg PZT ceramics and other titanates
77.55.-g Dielectric thin films
77.80.-e Ferroelectricity and antiferroelectricity
78.20.Ci Optical constants (including refractive index, complex dielectric constant, absorption, reflection and transmission coefficients, emissivity)
81.15.Cd Deposition by sputtering
64.70.K- Solid-solid transitions

Nucleation-type magnetization behavior in FePt (001) particulate films

T. Shima, K. Takanashi, Y. K. Takahashi, K. Hono, G. Q. Li, and S. Ishio

J. Appl. Phys. 99, 033516 (2006); http://dx.doi.org/10.1063/1.2169878 (5 pages) | Cited 9 times

Online Publication Date: 10 February 2006

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Nucleation-type magnetization behavior is reported in sputtered FePt (001) films with an island structure, where the particles show a multiple-domain structure. A large coercivity HC of more than 50 kOe is achieved at an initial applied field of only 6 kOe. The magnetization behavior and the magnetic domain observation indicate clearly that domain walls are wiped out completely at a low applied field, and once domain walls are wiped out, it is hard to nucleate reversed domains in the particles, resulting in high HC. The remarkable nucleation-type behavior of magnetization is also found to give rise to anomalous minor loops when the applied magnetic field is alternated around zero and increased gradually.
Show PACS
75.70.Ak Magnetic properties of monolayers and thin films
75.70.Kw Domain structure (including magnetic bubbles and vortices)
75.50.Tt Fine-particle systems; nanocrystalline materials
75.60.Ch Domain walls and domain structure
75.60.Ej Magnetization curves, hysteresis, Barkhausen and related effects
Page 1 of 4 Pages Next Page | Jump to Page
Close

Google Calendar

ADVERTISEMENT

Your Recent History Recent History Help

Recently Viewed

  1. Fabrication of induced two-dimensional hole systems on (311)A GaAs
  2. Analysis of leakage current mechanisms in Schottky contacts to GaN and Al0.25Ga0.75N/GaN grown by molecular-beam epitaxy
  3. Optical and electrical transport properties of facing-target sputtered Al doped ZnO transparent film
  4. A photoemission model for low work function coated metal surfaces and its experimental validation
  5. Valence-band electron-tunneling measurement of the gate work function: Application to the high-κ/polycrystalline-silicon interface
Go to AIP Home
Copyright © American Institute of Physics
close